根据X轴上的时间绘制数据

Question

I am having a set of python lists and I want to plot a graph with matplotlib in such a way that list of time is plotted in x axis and list of data is plotted in y axis.

code written by me looks similar to :

time =['16:40:48','16:45:48','16:50:48','16:55:48','17:00:48','17:05:48','17:10:48']

data1 = ['702','683','696','666','688','694','699']


fig = plt.figure(figsize=(20.0, 16.0))

ax = fig.add_subplot(1,1,1)

dates = matplotlib.dates.date2num(time)


ax.plot_time(dates,data1)


ax.xaxis.set_major_locator( mdates.MinuteLocator(interval=5) )
ax.xaxis.set_major_formatter( mdates.DateFormatter("%H:%M:%S") )
plt.grid(True)

plt.show()

But this gives me an error saying :

AttributeError: 'str' object has no attribute 'toordinal'

I have looked into somne post regarding the similar issue but couldnt find a desired solution for my problem.

Answer 1

From the documentation:

matplotlib.dates.date2num(d):
d is either a datetime instance or a sequence of datetimes.

You'll have to convert your time- strings to datetime objects first. Anyway, you won't need to convert them to "nums", just plot them and you're fine.

For creating datetimes, simply use list comprehension:

datetimes = [datetime.datetime.strptime(t, "%H:%M:%S") for t in time]

and then

ax.plot(datetimes, data1)